
Phineas Flynn and his stepbrother, Ferb Fletcher, are determined to make every day of their summer vacation fun. They try building a full-scale roller coaster, becoming musicians, building a backyard beach, and traveling back in time to meet dinosaurs. Their family pet, Perry the Platypus, doubles as a secret agent and battles evil. Meanwhile, older sister Candace is tattling on them to Mom and Dad, though she can never seem to catch them in the act.

Doof becomes a Mothman; the boys make a movie set.

Meap enlists Candace and the kids to help bust his nemesis, Mitch, before he can steal a long-lost treasure hidden somewhere on Earth.

While Buford is sick, Baljeet makes him watch an episode of his favorite show, "Space Adventure!"; Isabella works with Doof to bake a giant pastry to impress foreign emissaries.

Doof gathers energy from people exercising while the kids pilot a boat that surfs concrete; Candace and Jeremy make a Perry documentary as the kids play an extreme game of croquet.